supersymmetry

a hypothetical symmetry among groups of particles containing fermions and bosons, especially in theories of gravity (supergravity) that unify electromagnetism, the weak force, and the strong force with gravity into a single unified force.

(s'pər-sĭm'ĭ-trē) A theory of physics that states that for each boson (a subatomic particle that carries a fundamental force, such as the photon, which carries the electromagnetic force) there is a corresponding fermion with the same mass. The theory is an attempt to unify the fundamental forces of matter under one theory. Supersymmetry has not been shown to hold in the real world, though some scientists suspect that evidence for it may be found only at extremely high energies; some also believe that certain particles predicted by the theory may make up dark matter.